Specify Your Internet Settings 
25
 Nighthawk AC1900 WiFi Cable Modem Router
3.  Enter the modem router user name and password.
The user name is admin. 
The default password is password. The user name and 
password are case-sensitive.
The BASIC Home screen displays.
4.  Select ADV
ANCED > Setup > WAN Setup. 
5.  In the MTU Size field, enter a value from 64 to 1500.
6.  Click the Apply button.
Your change is saved.
If you suspect an MTU problem, a common solution is to change the MTU to 1400. If you are 
willing to experiment, you can gradually reduce the MTU from the maximum value of 1500 
until the problem goes away
. The following table describes common MTU sizes and 
applications. 
Table 1.  Common MTU sizes  
MTU Application
1500 The largest Ethernet packet size. This setting is typical for connections that do not use 
PPPoE or VPN, and is the default value for NETGEAR modem routers, adapters, and 
switches.
1492 Used in PPPoE environments.
1472 Maximum size to use for pinging. (Larger packets are fragmented.)
1468 Used in some DHCP environments.
1460 Usable by AOL if you do not have large email attachments, for example.